1mL/kg of .25% bupivacaine for outpatients, 1mL/kg of .25% bupivacaine with 1mcg/kg of clonidine for inpatients. I know studies show that clonidine is safe but I don't use it on outpatients because of concern of too much sedation with addition of oral opioids in a non-monitored setting.
Straight bupivacaine seems to last 5-6hrs and you can pretty reliably double that with the clonidine.
I'll do caudals for hernia repairs, ostomy takedowns, femoral fractures (amazing how it helps kids transition to SPICA casts...just have to make sure they leave enough room to access the hiatus in a sterile fashion)...as well as liberally in the urologic population.
TAP vs. Epidural vs. Paravertebral are decided on a case by case basis...they all work fine but varying operative circumstances and surgeon/family expectations keep me utilizing each of them with some frequency. It doesn't get much easier/faster than a caudal, so I suspect that they will always have a place in my practice for non-urologic surgeries.